Abstract: In one aspect, the invention provides fluorescent probes and assays. The probes include a fluorophore-quencher pair that undergoes a switch from dark to fluorescent in response to a reaction of the quencher. The switch of the probe from dark to fluorescent is typically mediated by an enzyme that acts directly or indirectly on the quencher, interfering with its ability to quench fluorescence emission from the fluorophore. In another aspect, the invention provides a reporter gene assay system and methods of using this system. The assay system includes a fluorophore-quencher probe and an enzyme that acts directly or indirectly on the quencher, increasing the fluorescent emission of the fluorophore. In still other aspects, the invention provides nucleic acid constructs and cells expressing the peptide products of these constructs. In assays of the invention, the presence of a target substance is detected by the switching of fluorescence mediated by the change in oxidation state of the quencher.

Abstract: A method was developed for the screening of antioxidant efficacy in food and feed matrices. The novel method uses radical initiators to accelerate the oxidation process. Consequently the screening of the oxidation process can be performed at significantly lower temperatures compared to the existing methods. The use of initiators improves the correlation between accelerated screening and real shelf life. This resolves an important issue that is frequently raised concerning the applicability of accelerated oxidation tests conducted at high temperatures. Furthermore feed and food products can be analyzed in their original states because lower temperatures have less influence on the product matrix.

Abstract: A process for the preparation of an oxirane, aziridine or cyclopropane of formula (I), wherein X is oxygen, NR4 or CHR5; R1 is hydrogen, alkyl, aryl, heteroaromatic, heterocyclic or cycloalkyl; R2 is hydrogen, alkyl, aryl, heteroaromatic, CO2R8, CHR14NHR13, heterocyclic or cycloalkyl; or R1 and R2 join together to form a cycloalkyl ring; R3 and R10 are, independently, hydrogen, alkyl, aryl, heteroaromatic, CO2R8, R83Sn, CONR8R9, trialkylsilyl or triarylsilyl; R4 is an electron withdrawing group; R5 is alkyl, cycloalkyl, aryl, heteroaromatic, SO2R8, SO3R8, COR8, CO2R8, CONR8R9, PO(R8)2, PO(OR8)2 or CN; R8 and R9 are independently alkyl or aryl; and R13 and R14 are independently hydrogen, alkyl or aryl is provided. The process comprises degrading a compound of formula (II), (IIa), (IIb) or (IIc): wherein R3 and R10 are as defined above; Y is a cation; depending on the nature of Y, r is 1 or 2; and L is a suitable leaving group, to form a diazo compound.

Abstract: The present invention relates to a rapid method for the detection of ischemic states and to a kit for use in such a method. Provided for is a rapid method of testing for the existence of and quantifying ischemia based upon method of detecting and quantifying the existence of an alteration of the serum protein albumin which occurs following an ischemic event; methods for detecting and quantifying this alteration include evaluating and quantifying the cobalt binding capacity of circulating blood, analysis and measurement of the ability of serum albumin to bind exogenous cobalt, detection and measurement of the presence of copper in a purified albumin sample and use of an immunological assay sepcific to the alterated form of serum albumin which occurs following an ischemic event.

Abstract: The present invention teaches a marker useful for detection and measurement of free radical damage. Specifically, the invention takes advantage of alterations which occur to the N-terminus of the albumin molecule, a circulating protein in human blood, in the presence of free radicals. These alterations effect the ability of the N-terminus of the albumin molecule to bind metals. Methods for detecting and quantifying this alteration include evaluating and quantifying the cobalt binding capacity of an albumin containing sample, analysis and measurement of the ability of albumin to bind exogenous cobalt, detection and measurement of the presence of copper in a purified albumin sample and use of an immunological assay specific to the altered form of serum albumin which occurs following free radical damage.

Abstract: A composition and method for determining the presence of leukocyte cells, esterase or protease in a test sample are disclosed. The composition contains a lactate ester having the structure ##STR1## wherein A is an alcohol blocking group, and wherein B-O- is a residue of compound B-OH and provides a detectable response when the lactate ester is hydrolyzed; and a buffer. One class of lactate ester has the structure ##STR2## wherein X is O, S or NR.sup.2, R is aryl or lower alkyl, R.sup.1 is hydrogen or lower alkyl, and R.sup.2 is hydrogen, lower alkyl or aryl.

Abstract: A composition for detecting the presence and concentration of a substance such as uranyl, comprising an organohalide covalently bonded to an indicator for said substance. The composition has at least one active OH site for forming a complex with the substance to be detected. The composition is made by reacting equimolar amounts of the indicator and the organohalide in a polar organic solvent. The absorbance spectrum of the composition-uranyl complex is shifted with respect to the absorbance spectrum of the indicator-uranyl complex, to provide better spectral resolution for detecting uranyl.

Abstract: A kit including a reagent containing a buffer suitable for maintaining the pH of the reagent between 3-7, sulfanilic acid or sulfanilamide, a cupric soluble salt and an alkaline metal nitrite, for the detection and determination of bilirubin in the urine providing precise results and ready automation of the procedure, characterized in that it is a stable combination of all the substances used for such analysis.

Abstract: A method for detecting ischemic states in a patient by contacting a sample of serum, plasma, fluid or tissue with a metal ion capable of binding to metal ion binding sites in the sample to form a mixture, and then detecting the presence of unbound metal ions to determine the occurrence of ischemia. The reagents required to perform the method are incorporated into a test kit.

Abstract: In the assaying of direct and indirect bilirubin, it is has been found that organic compounds, capable of undergoing diazotization to products having absorption spectrum substantially identically to bilirubin, can be used as a calibration standard. Typical of these organic compounds is ANS (8-anilino-1-naphthalene-sulfonic acid). However, these compounds do not have the typical yellow color of bilirubin. It was also discovered that this deficiency can be corrected by the addition of methyl or ethyl orange. When combined, these compounds provide a liquid control stable at room temperature for 12 months or more.

Abstract: A procedure for establishing the presence of live housedust mites in a textile sheet-like article, in which the housedust mites are allowed to migrate onto the surface of the article to be tested or are caused to start such a migration, if appropriate by the action of heat, the housedust mites which have migrated being picked up at this point and subsequently identified.

Abstract: A reagent containing a buffer suitable for maintaining the Ph of the reagent between 3-7, sulfanilic acid or sulfanilamide, a cupric soluble salt and an alkaline metal nitrite, for the detection and determination of bilirubin in the urine providing precise results and ready automation of the procedure, characterized in that it is a stable combination of all the substances used for such analysis.

Abstract: The present invention concerns a method of quantitatively determining the amount of bacterial endotoxin present in a periodontal pocket of a subject. The method comprises:a) obtaining a sample from the periodontal pocket of the subject;b) contacting the sample with an amebocyte lysate under conditions so as to activate an enzyme capable of cleaving a bond between an arginyl group and a nitrogen-containing group;c) contacting the activated enzyme with a substrate comprising an arginyl group and a suitable nitrogen-containing group bound to the arginyl group so as to form an amine;d) treating the resulting amine to produce a detectable product; ande) quantitatively determining the amount of product formed and thereby the amount of bacterial endotoxins present in the periodontal pocket.

Abstract: Novel reagent compositions and an assay method for the measurement of total and direct bilirubin are disclosed. The reagent compositions comprise an aqueous solution of at least one betaine selected from the group of alkyl betaine, betaine and betaine hydrate, a sulfanilamide diazonium salt, iodide ions and sulfamic acid. In the measurement of total bilirubin, alkyl betaine serves as an accelerator/solubilizer for the reaction of unconjugated bilirubin, and the alkyl betaine, betaine or betaine hydrate, together with iodide ions, minimizes or substantially eliminates interference from hemoglobin and lipemia.

Abstract: There is provided a stable liquid single reagent solution for determination of conjugated bilirubin in biological fluids which comprises an essentially surfactant free aqueous solution containing a positive amount of a water soluble organic sulfate, a diazonium salt, urea and a heavy metal complexing agent, the solution having an acidic pH and stable for at least 18 months at 2.degree. to 8.degree. C. Also disclosed is a method of forming such a reagent.

Abstract: Disclosed is a process for measuring an amount of all bilirubins in a specimen, comprising deconjugating conjugated bilirubins with a reagent comprising an enzyme capable of deconjugation to form the unconjugated bilirubin, and determining an amount of the unconjugated bilirubin in the specimen, and a reagent therefor. The present invention also provides a process for measuring an amount of the unconjugated bilirubin in a specimen, comprising oxidizing and eliminating conjugated bilirubins in the specimen with an oxidizing agent capable of oxidizing bilirubins, in the presence of a metal ion forming a complex with the bilirubins and a surfactant at pH 6.5 or less, and determining an amount of the unconjugated bilirubin in the specimen, and a reagent therefor.

Abstract: Disclosed is a method for measuring the rate and extent of cure of a resin system undergoing polymerization which entails adding at least one multifunctional fluorescent dye to the resin system undergoing polymerization, the dye being one which initially forms a complex with itself or other components of the system and subsequently chemically reacts with the resin and whose degree of fluorescent emission varies in accordance with the degree of reaction with the resin, polymerizing the resin, simultaneously measuring the fluorescence of the resin system, and comparing the measured fluorescence with pre-existing data correlating the observed values with the rate and extent of polymerization, thereby enabling the rate and extent of polymerization of the resin system under evaluation to be determined.

Abstract: A process for detecting the presence of living cells suspended in an aqueous medium preferably at a nearly neutral pH, which comprises:(a) reducing a tellurapyrylium Te(IV) dihydroxide (TPDH) with cells, optionally while using a substituted benzoquinone electron transfer agent to assist the reduction, thereby producing a change in light absorbance and(b) sensing the change in absorbance to detect or quantify the presence of the cells.The light absorbance change comprises the appearance of a new spectral peak from the product formed by reduction of the Te(IV) dihydroxide. The new peak has a high extinction coefficient in the near infrared region of the electromagnetic spectrum, i.e., away from the spectral region where some biological components cause spectral interference. Consequently, detection methods provided by this invention have a high degree of sensitivity and are comparatively free from spectral interference caused by materials commonly present in biological materials.

Abstract: There is provided a bilirubin assay composition and method of its formation. The composition comprises water, EDTA, of water soluble organic sulfate present in a concentration of about 1 g/l to solution saturation, caffeine in a concentration of from 0 to about 100 g/l and a diazonium salt in a concentration of about 0.05 to about 1.5 mM. The solution has a pH of from about 3.5 to about 6.0 and is stable for at least 18 months at 2.degree. to 8.degree. C.

Abstract: A new and improved test device and method of determining the presence and concentration of fructosamines in a test sample. The test device includes a test pad comprising a carrier matrix incorporating an indicator reagent composition capable of interacting with fructosamines to produce a detectable or measurable response. The carrier matrix of the device includes a bibulous matrix, such as filter paper, or a nonbibulous matrix, such as a polymeric film. In addition, a new and improved indicator reagent composition comprising a dye, such as tetrazolium violet; a suitable buffer; and an accelerator compound is incorporated into the carrier matrix to provide a test pad demonstrating sufficient color resolution and having sufficient sensitivity to fructosamines in a test sample. Therefore, a fast, more accurate and trustworthy fructosamine assay of a liquid test sample, such as whole blood or serum, is achieved.

Abstract: An analytical element for quantitative analysis of bilirubin in a liquid sample by a diazo method, characterized in that the bilirubin detection reagent is a non-diffusive aryldiazonium salt having in the aryl group at least one substituent selected from the group consisting of an alkoxycarbonyl group, an alkylaminosulfonyl group and an alkylaminocarbonyl group.

Abstract: A process and reagent kit for the determination of direct and total bilirubin in body fluids by coupling the bilirubin with a diazonium salt and determining the extinction change thereby brought about, by usual methods.The coupling is carried out in the presence of a buffer which adjusts the test solution to a weakly acidic to approximately neutral pH value preferably between pH 3.5 and 8. The diazonium salt is of the formula: ##STR1## in which R.sub.1 is a hydrogen or halogen atom or a lower alkyl, lower alkoxy or benzoylamino radical, R.sub.2 is a hydrogen atom or a lower alkyl or lower alkoxy radical, R.sub.3 is a hydrogen or halogen atom or a lower alkyl or lower alkoxy radical, whereby R.sub.1 and R.sub.3 do not simultaneously represent halogen atoms, and X is an anion forming a storage-stable salt with the diazonium cation.

Abstract: A method for determining the extent of polymerization of a polymer system consisting of adding a fluorescent label, the label having a reactivity similar to the reactivity of the curing agent, to the polymer system and measuring the fluorescence intensity proportional to cure species concentration during polymerization. The fluorescence intensity of the label exhibits sensitive changes throughout the polymerization process, allowing one to follow cure reactions in a quantitive way by measuring fluorescence, especially in the latter stages of cure. The cure species composition, reactivity ratio, activation energy and weight-average molecular weight can also be determined by adding a label and measuring the UV-VIS spectra in addition to the fluorescence intensity.

Abstract: Certain reducible compounds are useful in analytical compositions, elements and methods, e.g. for assays of bacterial cells. These compounds comprise a moiety which provides a detectable species (e.g. a dye) when released from the compound in an environment of pH 9 or less (i.e. physiological pH). Structurally, the reducible compounds are aromatic derivatives or quinones having suitable substituents which promote varying amounts of moiety release at physiological pH. When reduced at about pH 7, the preferred compounds release at least 50% of the available detectable species within 30 minutes.

Abstract: Certain water-compatible reducible compounds are useful in analytical compositions and elements for assay of various analytes, e.g. microorganisms. These compounds comprise a moiety which provides a detectable species (e.g. a dye) when released from the compound at physiological pH. Further, these compounds are aromatic derivatives or quinones having water-compatibilizing substituents which allow them to be used in compositions without the use of surfactants.

Abstract: The present invention provides stabilized compositions of tetrazolium salts for analytical purposes which contain 1 to 10 moles of a complex forming acid which is soluble in polar solvents, per mole of tetrazolium salt. Additionally, the invention provides a process for the detection of reducing materials, wherein a stabilized composition as described is added to a test batch.

Abstract: The invention provides an aerosol spray reagent for the presumptive identification of cocaine, cocaine salts and phencyclidene comprising cobalt thiocyanate, a polyol, an aliphatic solvent, a nonionic emulsifier and a silicon antifoam agent, as well as providing a multi-reagent test kit for the presumptive identification of cocaine, cocaine salts and phencyclidene comprising a first aerosol spray reagent as defined and a second reagent which produces a color reaction in the presence of trace amounts of a diazotisable amine.

Abstract: The invention relates to a procedure to establish the presence of allergen-containing housedust, as results when or after housedust mites occur, in which samples of dust present in buildings are thoroughly suspended in a aqueous-alcoholic alkali metal hydroxide solution and, with the resulting extract, a color reaction using an aromatic diazo compound is carried out, the color reaction being evaluated with respect to its occurrence as an indication of the pollution of the dust with housedust mite residues. According to a particular embodiment, a paper treated with the aromatic diazo compound (and where appropriate with starch) is used for carrying out the color reaction. A further aspect of the invention involves quantitatively determining the allergological activity resulting from housedust mites in housedust samples.

Abstract: A microbiological culture test process for detecting the presence of nitrate-reducing microorganisms in an inoculum sample, which comprises(a) culturing a microorganism to be tested in the presence of adequately nitrite-free nitrate, for a period sufficient to allow reduction of nitrate by any microorganism (if present) that has the capacity to reduce nitrate to nitrite, (e.g. 1-6 hours);(b) exposing the culture medium after culture to (diazotizing) acid conditions in the presence of an amino-containing fluorophor thereby to cause diazotization of the fluorophor to the extent of any nitrite present in the medium to form a diazonium derivative (or further reaction product thereof) which is substantially less fluorescent (or fluoresces at a substantially different wavelength) than said amino-containing fluorophor, and(c) assessing the fluorescence of the culture medium as treated by step (b), thereby to show a reduction in fluorescence in the presence of a nitrate-reducing microorganism.

Abstract: The invention provides a stable solid reagent for use in a prepackaged test kit for the detection of cannabinoids comprising a diazonium salt which undergoes characteristic color change when combined with a cannabinoid under basic conditions, the salt comprising an anion capable of causing the entire salt including the diazonium cation thereof to dissolve in an organic solvent when combined therewith to form a stable liquid reagent for the detection of cannabinoids. The invention also provides a stable liquid reagent comprising the aforementioned diazonium salt and an organic solvent as well as providing prepackaged reagent test kits containing the aforementioned reagents and methods for detecting cannabinoids using the reagents of the invention.

Abstract: A method for determining the extent of polymerization of an epoxy system consisting of adding a fluorescent label, the label having a reactivity similar to the reactivity of the curing agent, to the epoxy system and measuring the fluorescence intensity during polymerization. The fluorescence intensity of the label at its emission maximum increases sharply with polymerization, allowing one to follow cure reactions in a quantitative way by measuring fluorescence, especially in the later stages of cure beyond gelation. The composition, reactivity ratio, activation energy and weight-average molecular weight can also be determined by adding a label, such as p,p'-diaminoazobenzene (DAA) or trans diamine-stilbene (DAS), to mimic the reactivity of the curing agent, such as diaminodiphenyl sulfone (DDS) or methylene dianiline (MDA), and measuring the UV-VIS spectra in addition to the fluorescence intensity.

Abstract: A multilayer analytical element for analysis of analyte in a liquid sample comprising a liquid sample-spreading layer, a reagent layer containing a diazonium salt, and a liquid-impermeable light-transmissive support, being laminated in this order, in which said reagent layer contains a sulfonic acid group-containing polymer having at least 10 molar % of a repeating unit selected from those consisting of a sulfoalkyl group and sulfophenyl group. The analytical element can be an element comprising a porous reagent layer containing a diazonium salt and the liquid-impermeable light-transmissive support, being laminated in this order.

Abstract: An improved reagent combination of the type comprising a first solution comprising an aryl amine and an acid; and a second solution comprising a nitrite compound. The regent combination is characterized in that is further comprises a salt, wherein the salt is present in any preselected distribution in the solutions.Also, an improved method for colorimetrically determining bilirubin in a sample comprising mixing an aliquot of the above first solution with an aliquot of the above second solution to form a stable diazo reagent; contacting a sample to be assayed with a total bilirubin accelerator buffer system to form a prereaction medium; contacting the prereaction medium with the stable diazo reagent; and measuring the color of the azobilirubin formed form the coupling reaction of the stable diazo reagent with the bilirubin present in said sample.In addition, an improved method for producing a diazo reagent of the type comprising reacting an aryl amine with a nitrite compound in the presence of an acid.

Abstract: A composition comprising a 9-fluorenone-2-diazonium salt, an acid or acidic salt which is solid at normal temperatures, and if necessary an anionic surface active agent can produce a vivid red color instantly by reacting with urobilinogen without interfered with bilirubin.

Abstract: A composition and test device for determining the presence of an analyte selected from leukocytes, esterase and protease in a test sample. The composition comprises an ester capable of producing a detectable response upon interaction with said analyte, and a diazonium salt having the structure ##STR1## in which A.sup.- is an anion, and R same or differ, is H, lower alkyl, aryl, or both of R together form a fused ring system, and in which R' is H, OH or lower alkyl.

Abstract: The present invention provides stabilized compositions of tetrazolium salts for analytical purposes, wherein they contain 1 to 10 moles of a complex-forming acid which is soluble in polar solvents per mole of tetrazolium salt.The present invention also provides a process for the detection of reducing materials, wherein one of the above stabilized compositions is added to a test batch.

Abstract: An improved conjugated (direct) bilirubin assay comprises treating a sample to be assayed with a buffer having a pH of about 4 to 5 and containing iodide ions thereby decreasing the oxidation of hemoglobin to methemoglobin and preventing conjugated bilirubin from being oxidized to biliverdin. The iodide also prevents the destruction of the azopigment by the hemoglobin. The assay further comprises adding a diazo reagent to the treated sample, incubating the resulting mixture, adding ascorbic acid, alkaline tartrate and a caffeine reagent and then reading the absorbence at 600 nm. The concentration of direct bilirubin is calculated by comparison to the absorbance of unconjugated standard(s) analyzed by a method for total bilirubin. The improved assay is more accurate than prior art methods because hemoglobin interference is negligible. In a preferred embodiment the buffer is sodium acetate buffer having a pH of about 4.75 which contains 3 to 30 grams/L of potassium iodide.

Abstract: Diazonium salts which are useful in an assay for bilirubin are disclosed. The novel salts have the structural formula: ##STR1## wherein X.sup.- is a stabilizing anion, Y is CO-- or SO.sub.2 --; and R.sup.1 and R.sup.2 are independently selected from hydrogen, alkyl, aryl, carboxyalkyl and hydroxyalkyl providing R.sup.1 and R.sup.2 are not both hydrogen; R.sup.3 and R.sup.4 are independently selected from groups such that the sum of the Hammett sigma values for R.sup.3 and R.sup.4 does not exceed +0.4 or R.sup.3 and R.sup.4 represent the carbon atoms necessary to complete a fused carbocyclic ring structure. Reagent compositions, analytical elements and methods which use the described diazonium salt are also disclosed.

Abstract: An improved reagent and method for assay of total bilirubin in biological fluids utilizes diazo sulfanilic acid to convert bilirubin to azobilirubin which is then quantitatively measured. The improved reagent and method include the solvent accelerator tetramethylene sulfone. The use of tetramethylene sulfone as also allows the use of nonionic surfactants, obviating the need for serum blank correction in highly lipemic serum. Furthermore, the use of tetramethylene sulfone and nonionic surfactants renders the reagent mixture less viscous facilitating automated analysis.

Abstract: A test agent for the detection of coupling compounds in liquids is described, which essentially consists of an adsorbent matrix containing a diazonium salt as the reagent and a phosphonium salt to stabilize said test agent. Furthermore there is described a process for the preparation of said test agent.

Abstract: A test kit for the determination of bilirubin in a test sample is disclosed. It comprises a reagent capable of producing a color change or other detectable response in the presence of bilirubin, and a test mat comprising finely divided silica gel. The kit is utilized by wetting the test mat with a portion of a liquid test sample suspected of containing bilirubin, contacting the wetted mat with the reagent, causing the reagent to at least partially wet the mat and observing the appearance of a color change or other detectable response.

Abstract: A multilayer analytical element for quantitative analysis of bilirubin in a liquid sample by a diazo method, which comprises a laminated structure consisting essentially of:(1) a porous reagent layer containing an acidic binder and a diazonium salt being reactive to bilirubin to produce azobilirubin;(2) an absorbent layer capable of absorbing an excessive liquid portion; and(3) a liquid-impermeable light-transmissive support.